An impressive image of the cometary globule CG4 has been captured by the ESO’s Very Large Telescope (VLT). Although their name associates them with comets, cometary globules are not at all related to comets and are actually a type of nebula. It is in fact a subtype of Bok globule, which is very dense, very compact and very cold nebula. Studying these globules is very difficult as they emanate no light and often appear as dark patches in the sky. Although they are some of the coldest objects of the universe, a very warm core often burns inside, which might be a forming star or multiple stars.
The cometary globule CG4 is also known as God’s Hand and its one side has been blown outwards forming a long tail similar to a comet. It is one of the many cometary globules located in the Gum Nebula and all of them have tails which trail away from the Vela supernova remnant. The tails might have formed due to the exploding star. There is another hypothesis behind its shape, according to which, the stellar winds and ionising radiation from very hot, very large OB stars nearby have caused this shape.
The globule is usually very faint and is located in the constellation of Puppis. It is composed of very dark and very dense material. Image captured by European Southern Observatory’s Very Large Telescope reveals that its head resembles a gaping mouth and is located 1.5 light-years across while its tail extends eight light years behind. The head of CG4, made up of thick cloud of gas and dust, is not glowing with its own light in the image; instead it is illuminated by the light of nearby stars. CG4 is gradually eroding due to the radiations from nearby stars but it is still maintaining its role as a stellar nursery and new stars are forming in its depths.